Rotor wings are known, for example, from DE 693 03 152 T2. It comprises a stiff composite shell with an aerodynamic profile that extends lengthwise in accordance with the span of the rotor blade, and a tubular blade base that extends the stiff shell on the side of the rotor blade that is connected to a hub. The blade base comprises two complementary half-shells that are formed by an extension of one of two layered jackets which together form the rigid composite shell. The half-shells can also be designed so as to be separate, in other words independent of the rigid shell, and can be pushed onto a small cone on the blade, which cone is circular in cross section. By rotation of the rotor blade relative to the two half-shells on its longitudinal axis, an angle of incidence can be pre-set in an infinitely variable manner. However, production of this rotor blade has been shown to be expensive, and its service life has been shown to be inadequate.
GB 036 677 A2 and EP 0 296 014 A1 disclose respectively a rotor blade in a fiber reinforced composite design with a blade section and a coupling section for attaching the rotor blade to the hub of a drive device. A sleeve shaped control tube is tied to the coupling section.
EP 1070662 A1 discloses a rotor blade with a flexing beam with integrated soft region for impact, folding motion and torsion. Damping elements are made between a soft-folding region of the flexing beam and the end of a transition region. They lie in the folding plane of the blade to the side of the flexing beam.
U.S. Pat. No. 4,975,021 A discloses a rotor, in particular a helicopter rotor, whereby the movement of the pitch angle of the rotor blade relative to a rotor hub is provided either by a blade neck with torsional flexibility disposed between a blade root and a blade wing or by a blade connection on a rotor hub arm with torsional flexibility. The pitch angle control for the blade is provided by a steering rod coupled to a torsionally stiff blade control casing extending coaxially without making contact along the blade neck or the rotor hub arm up to the blade wing or to the blade root. The control casing is supported on the blade root or rotor hub by at least one brace, which brace, in the longitudinal direction of the blade, has a T-shape. The vertical section of the T-shape is coupled to the blade control casing and the T-base is coupled with torsional flexibility to the blade root or the rotor hub arm, whereby the connection to the base is limited to both of the extremities of the base. Thus, the brace provides both a supporting function for the blade control casing and acts as a torsion bearing that enables rotational movement of the blade control casing and thus change of the blade pitch angle.